The body mass and internal organ size may change with different environmental conditions and display phenotypic plasticity in amphibians. However, empirical evidence testing the theory of phenotypic plasticity is still scarce, especially for specific experiments associated with ever-changing food availability. The changes of body mass, as well as wet and dry mass of internal organs from five groups (feeding, fasting for one week, fasting for two weeks, re-feeding for one week, and re-feeding for two weeks) were measured in Asiatic Toads (Bufo gargarizans) captured at Dingyuan County, Anhui Province. Two-way ANOVA was performed to analyze the sex and group differences for body mass. Two-way ANCOVA with body mass (or carcass dry mass) as a covariate was performed to analyze the sex and group differences for carcass wet mass and dry mass as well as the wet mass and dry mass of internal organs. All values are represented as the mean ± SE, and P <0.05 was considered as the level for statistical significance. The software SPSS (13.0, USA) was used for data analysis. The results were as follows: 1) Body mass, carcass wet mass and dry mass did not show significant sex (Table 1, all P > 0.05) and group (Table 1, all P > 0.05) differences. 2) Stomach wet mass (Fig. 1a, P < 0.05) and dry (Fig. 1b, P < 0.05) mass, as well as large intestine wet mass (Fig. 1c, P < 0.05) was heavier in females than in males. However, no sex difference was observed for the wet mass (Table 2, all P > 0.05) and dry (Table 3, all P > 0.05) mass of other internal organs (small intestine, thymus, heart, liver, lung, fat body, spleen and kidney). In males, no group difference was found for stomach wet mass (Fig. 1a, P < 0.05) and dry (Fig. 1b, P < 0.05) mass, as well as large intestine wet mass (Fig. 1c, P < 0.05). In females, stomach dry mass was heavier in feeding group than that in the group re-feeding for one week (Fig. 1b, P < 0.05), but no difference was observed for the wet mass of stomach (Fig. 1a, P < 0.05) or large intestine (Fig. 1c, P < 0.05). Small intestine wet mass was greatly declined in the group fasting for two weeks, lower than that of feeding group and re-feeding groups (Fig. 1d, P < 0.05). 3) Heart wet mass in the group fasting for one week was heavier than that in the group re-feeding for two weeks (Fig. 1e, P < 0.05). These results indicate that short-term fasting and re-feeding treatments had no obvious influence on Asiatic Toads at organismal levels; Asiatic Toads may mainly rely on enhanced heart functions induced by moderate starvation and the plasticity of digestive tract at organic levels to cope with changing food availability.